Correctly parse webpack to extract third-party libraries

When we use webpack to package, we often want to extract the third-party library separately, use it as a stable version file, and use the browsing cache to reduce the number of requests. There are two commonly used methods to extract third-party libraries. This article mainly introduces the correct posture of extracting third-party libraries with webpack. There are two commonly used methods to extract third-party libraries. This article introduces these two methods in detail. For those who are interested You can learn about it, I hope it can help everyone.

1. CommonsChunkPlugin

2. DLLPlugin

Difference: The first type must be packaged every time The third-party library also runs packaging once. The second method only packages the project file each time. We only need to quote the third-party compressed file packaged for the first time.

CommonsChunkPlugin method introduction

Let’s take vue as an example

const vue = require('vue')
{
 entry: {
 // bundle是我们要打包的项目文件的导出名字， app是入口js文件
 bundle: 'app'，
 // vendor就是我们要打包的第三方库最终生成的文件名，数组里是要打包哪些第三方库, 如果不是在node——modules里面，可以填写库的具体地址
 vendor: ['vue']
 },
 output: {
  path: __dirname + '/bulid/',
 // 文件名称
 filename: '[name].js'
 },
 plugins: {
 // 这里实例化webpack.optimize.CommonsChunkPlugin构造函数
 // 打包之后就生成vendor.js文件
 new webpack.optimize.CommonsChunkPlugin('vendor', 'vendor.js')
 }
}

Then package the generated file and introduce it into the html file

<script src="/build/vendor.js"></script>
 <script src="/build/bundle.js"></script>

Introduction to DLLPlugin method

First prepare two files

1. webpack.config.js

2. webpack.dll.config.js

The webpack.dll.config.js file is configured as follows

##

const webpack = require('webpack')
const library = '[name]_lib'
const path = require('path')

module.exports = {
 entry: {
 vendors: ['vue', 'vuex']
 },

 output: {
 filename: '[name].dll.js',
 path: 'dist/',
 library
 },

 plugins: [
 new webpack.DllPlugin({
  path: path.join(__dirname, 'dist/[name]-manifest.json'),
  // This must match the output.library option above
  name: library
 }),
 ],
}

Then webpack.config The .js file configuration is as follows

const webpack = require('webpack')

module.exports = {
 entry: {
 app: './src/index'
 },
 output: {
 filename: 'app.bundle.js',
 path: 'dist/',
 },
 plugins: [
 new webpack.DllReferencePlugin({
  context: __dirname,
  manifest: require('./dist/vendors-manifest.json')
 })
 ]
}

Then run

$ webpack --config webpack.dll.config.js
$ webpack --config webpack.config.js

html reference method

<script src="/dist/vendors.dll.js"></script>
<script src="/dist/app.bundle.js"></script>

Related recommendations:

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Detailed explanation of vue Load components on demand webpack require.ensure

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